[API Server] Add security context to Ray Cluster

[han-steve]

Why are these changes needed?

Adding the ability to customize the security context for a ray cluster. This is useful for adding necessary permissions to profile a ray cluster. For example, for py-spy to work, we need to add

# `py-spy` is a sampling profiler that requires `SYS_PTRACE` to read process memory effectively.
# Once enabled, you can profile Ray worker processes through Ray Dashboard.
# For more details, refer to:
# https://docs.ray.io/en/latest/ray-observability/user-guides/debug-apps/optimize-performance.html#python-cpu-profiling-in-the-dashboard
securityContext:
  capabilities:
    add:
    - SYS_PTRACE

as documented here.

Checks

• I've made sure the tests are passing.
• Testing Strategy
  • Unit tests
  • Manual tests
  • This PR is not tested :(

[YQ-Wang]

Left some comments, thanks!

[YQ-Wang]

cc @kevin85421 @andrewsykim

[kevin85421]

Yiqing has already approved the PR. Merge.